Method of unlocking ore bodies to extract sulphur and iron therefrom



Dec.. 2l, 1937. H. c. WOLF Wm METHOD OF UNLOCKING ORE BODIES TO EXTRACT SULPHUR AND IRON THEREFROM Filed April l2, 1955 Patented Dec. 2l, 1937 NUNITI-:D STATES' ME'rnon oF UNLocKrNc.` ons BODIES 'ro Ex'rnAc'r sULrnUn-AND moN 'rnmm-v FROM Harry Comer Wolf, Indianapolisylnd., assignor to lrsugo Consolidated Mines, Limited, In-

dianapolis, Ind., a corporation of Canada i Application April l2, 1935, Serial No. 15,980

14 Claims.

My method is designed especially for the purpose of extracting sulphur and iron from pyrltes and recovering pure sulphur and a very fine quality of sponge iron. It will be obvious from 5 a study of the process as hereinafter described that it may also be used on other types` of rock.`

The object of my invention is to provide a method or process which when employed, will permit the recovery of finely divided sulphur and sponge l iron from pyrites which, absent my invention,

could not be handled advantageously.

In order to show clearly the various steps of my method, I have illustrated diagrammatically the process in the accompanying drawing of a l ilow sheet which is hereunto annexed and made a part of this specification. This sheet is supplied with appropriate legends, an inspection of which, in connection with the hereinafter contained specification, will aord a clear exposition of my invention.

It is to be understood that the flow sheet is furnished solely for illustrative purposes for my method does not require any specic type oi apparatus for its practice so long as it will func- 25 tion to obtain the necessary result.

The first step in' my method or process of unlocking ore bodies to permit the recovery of sulphur and iron is to pulverize the or'e until it is suiiiciently fine to pass through a screen of 200 sential for if the re is in large pieces the sulphur will remain locked in the rock. On the other hand if the particles areminute the sulphur will escape from the ore. Y

35 This is established by an examination of the iron under a microscope, after processing, which will discloseI that the iron has a sponge like appearance brought about by the escape of the sulphur.

40 The pulverizedore is then introduced into a retort whichis of a. standard for well known construction fromv which airis excluded. It should be understood that the heating may be carried out in any known type of heater such as rotary 45 retorts, or various other types of mechanical heaters. For convenience, I hereinafter employ the term heater to describe any form of apparatus in which the heating operation is carried on.

50 Heat is supplied to the retort preferably by electricity, gas, oil or coal, in the order named,

for while either form of heating may be utilized the ease of controlling the temperature of the retort will vary with the kind of heating medium 55 employed. The temperature of the retort is mesh. I have found in practice that this is es- A,

raised to the critical' temperature at which it starts operation. This is approximately 600 F. at which point the sulphur will begin to be converted into a vapor. The temperature is increased until it reaches 900 F. at which degree the operation will be complete for nearly all ores, although in practice I have carried it as high as 2100 F..for some classes of ore.

One ofthe vital differences in my method of recovering sulphur is that in the usual production of sulphur it forms a gas (SO2) which is a gas at normal temperatures while my process forms avapor (S) which is a solid at vnormal temperatures; pyrites, sulphur has always been produced in the presence of oxygen. Hence the sulphur is converted into sulphur dioxide (SO2) and the iron may be partially or Wholly oxidized, dependent upon the amount of xygen present.

During the heat treatment it is necessary inat In the past, in the treating of the pulverized material in the retort must be y kept in constant agitation; This may be done by revolving the retort, or by theuse of rabioles, shelves, or other desirable forms. of agitators o'perating within the retort. This is very important because it has been found in practice even with the ne pulverization of the material the same degree of recovery cannot be secured as the heatv will not penetrate the ore body because itdoes not possess sufficient thermal permeability.

The next step in my method is drawing the vapor off into a tank in which it is condensed.

There are'three ways in which this may be l' done and that means which is best adapted to the particular situation may be employed.

First the changing .from a solid to a vapor in the retort sets up a pressure in the retort and this pressure may be used to drive the vapor into the tank condenser. This movement is facilitated by the condensation in the tank which sets up a vacuum pull on the vapor line.

The second way is to` employ a so-called vacuumfor suction connection through a water or other 'seal to produce a reduced pressure in the condens- This must be preheated to approximate the maximum temperature of the -sulphur vapor as otherwise it would chill the vapor. The introduction of this heated inert gas will create a draft which 5 will aid in passing the vapor to the tank condenser. l

Ihe connection from the retort to the condenser tank must be by way of a two way vertical take-0E. 'I'his take-01T should be insulated to preserve the heat in the vapor. In some cases it may be necessary to heat the take-off. When this condition exists the flue gas may be utilized forthis purpose, if electricity is not being used for heating the retort, thus it may be done at a minimumof expense.

The height and the cross section area of the take-off must be in direct proportion to the ore being treated, and should be so proportioned as to prevent the dust particles from the rock from carrying over into the condensing tank orthe recovery of pure sulphur will be prevented. In practice I have found this height to be four or ve times the diameter of the retort, and the cro'ss section area suiciently so as not to act as an impedance to vapor iiow. 'I'his insures a low velocity of the vapor and allows sufcient lapse of time for the mechanical separation of any dust particles which may be carried by the vapor. In this manner I avoid the production of impure sulphur. I thus mechanically maintain the Vapor pure. It will be clear to those skilled in the art, that its chemical purity is maintained by keeping it from contact with oxygen.

The next step is to pass the residue of iron and rock remaining in the retort through the lower portion of the take-o into a tank-where it is quenched with water. A water seal must be provided for this tank to prevent any air from reaching the iron while it is hot. The residue is then conveyed through driers, this must be done promptly to avoid oxidization. This drying must not be done by a blast of air but preferably in the absence of air.

When electricity is not used for heating the retort, the flue gases may also be used to furnish heat for the driers. The dried residue is then carried past a plurality of magnetic separators of standard construction to recover the iron from the remaining non-magnetic ores. In practice I have found at least three are required to get rid of all impurities.

f The residue of rock remaining after the iron is removed is then ready to be treated for noble metals by well known methods. If copper is present by electrolytic or other methods; for lead or other minerals by well known methods, etc. By this method I have not only recovered sulphur from pyrites in paying qualities but it is of the purest form. While the iron is that form known as sponge iron which is conceded to be of the highest grade.

Having described my invention what I regard as new and desire to secure by Letters Patent is:

1. The method of unlocking ore bodies to produce sulphur and sponge iron, which consists o f continuously and completely agitating'the ore which is sufliciently iine to pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore to a temperature of 900 F. for a suiiicient length of time to dissociate the same into iron and sulphur.

2. 'I'he method of unlocking ore bodies to produce sulphur and sponge iron, which consists of continuously and completely agitating the ore `which is sumciently ilne to pass through a 200 meshscreen, in a chamber in the absence of oxidizing conditions to coincidentally dissociate the same into iron and sulphur.

l 3.r The method of unlocking ore bodies to produce sulphur and sponge iron coincidentally which consists of continuously and ,completely agitating the ore pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore until it is thoroughly permeated by the heat and thereby dissociating the ore into sulphur vapor and sponge iron.

4. The method of unlocking ore bodies to produce sulphur and sponge iron coincidentally, which consists of continuously and completely agitating the ore, pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore to 900 F. until eachcmolecule is permeated with the heat whereupon the ore will be dissociated into sulphur vapor and sponge iron.

5. 'I'he -method of unlocking ore bodies to produce sulphur and sponge iron coincidentally which consists of continuously and completely agitating the ore, pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence ofthe oxidizing conditions, heating said ore to a vtemperature from 900 to 2100 F. until each molecule is permeated with the heat whereupon the ore will be dissociated into sulphur vapor and sponge iron.

6. The method of unlocking ore bodies to produce sulphur and vsponge iron coincidentally which consists of continuously and completely agitating the ore, pulverized so that it Will passA through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore to a temperature of from 600 to 900 F. until each molecule is permeated with the heat whereupon the ore will be dissociated into sulphur vapor and sponge iron. l v

7. The method of unlocking ore bodies to produce sulphur and sponge iron coincidentally, which consists of continuously and completely agitating the ore, pulverizedA so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore until each molecule is permeated with the heat, whereupon the ore will be dissociated into sulphur vapor and sponge iron, discharging the sulphur and iron from said chamber into a two-Way vertlcal take-off, the sulphur passing upwardly while the iron passes downwardly. i

8. The method of unlocking ore bodies to produce sulphur and sponge iron coincidentally which consists of continuously and completely agitatng the ore, pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore until each molecule is permeated with the heat, whereupon the ore will be dissociated into sulphur vapor and sponge iron, discharging the sulphur and iron from said chamber into a two-way vertical take-olif, the sulphur passing upwardly into a condenser while the iron passes downwardly.

9. The method of unlocking ore bodies to provduce sulphur and sponge iron coincidentally which consists of continuously and completely agitating the-ore, pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore to 900 F. until each molecule is permeated with the heat at which the ore will be dissociated into sulphur vapor and sponge iron, disintegrating the reduced ore with water and thereafter drying the residue of ore in theabsence o! oxidizing condlto a source of reduced pressure to increase the tions 10. The method of coincidentally unlocking ore .y bodies to produce sulphur and sponge iron which consists of continuously and completely agitating the ore, pulverized so that it will pass through a 200 mesh screen, in a chamber in the absence of oxidizing conditions, heating said ore until each molecule is permeatedwith the heat for a sum- 10 cient length of time to dissociate the sulphur and iron, leading the resulting sulphur vapor into a condensing chamber where instantaneous condensation takes place, connecting said condenser i4. In the process of claim 3, the step of dis- 10 charging the sulphur by means of an inert gas.

HARRY COMER WOLF. 

